The long-term goal of this research is to elucidate the neural mechanisms of behavior and to understand the intrinsic mechanisms of the cerebral cortex. The combined behavioral-neurophysiological experiment is used. Monkeys are trained to perform certain behavioral acts, and then the electrical activity of single cortical neurons is recorded simultaneously with their performance. This experiment provides for a direct study of the relations between neuronal populations and behavior. Specific objectives are focused on frontal lobe mechanisms in motor behavior. Premotor and motor cortical areas are explored in the behaving monkey, and the activity of their neurons studied under conditions of increasing complexity in the motor and cognitive aspects of behavior. For the motor part, animals make simple movements aimed at targets in space, follow moving targets, or perform more complicated series of individual movements to reach a desirable target. For the cognitive part, the spatial and temporal uncertainties of motor tasks are manipulated (by varying the location and time of appearance of the target), the selection of certain target among others is varied (by varying the probabilities of reward associated with each possible target), and the rules of the translation of a stimulus configuration to a motor act is modified (e.g., to make a movement at 90 degrees to a given stimulus). A versatile X-Y eye-hand tracking apparatus provides for adequate degrees of freedom for the hand movements in space, and a PDP11/20 computer, wholly dedicated to this laboratory, allows control of the animal's behavior and analysis of the experimental data. The experiments outlined above are expected to cast some light on how the frontal cortex participates in decision making, planning and execution of motor acts. Concomitant measurements of eye movements (using EOG) should provide some insight into the neural mechanisms of eye-hand coordination. A more general aim of our research is the elucidation of some of the intrinsic mechanisms of neocortex. We hope that detailed histological analysis of the location of neurons with specific properties in the different cortical layers and the cortical surface will lead to a partial understanding of the nature of these mechanisms.